A New Lignan from Annona squamosa L. (Annonaceae) Demonstrates Vasorelaxant Effects In Vitro.

Esquamosan, a new furofuran lignan, has been isolated by bio-guided assays from the methanolic extract of the leaves of Annona squamosa L., and its structure was elucidated by spectroscopic methods. Esquamosan inhibited the rat aortic ring contraction evoked by phenylephrine in a concentration-dependent manner and showed an inhibitory effect on vasocontraction of the depolarized aorta with high-concentration potassium. The vasorelaxant effect by esquamosan could be attributed mainly to the inhibition of calcium influx from extracellular space through voltage-dependent calcium channels or receptor-operated Ca2+ channels and also partly mediated through the increased release of NO from endothelial cells. The ability of esquamosan to modify the vascular reactivity of rat aortic rings incubated with high glucose (D-glucose 55 mM) was then evaluated, and this furofuran lignan reverted the endothelium-dependent impairment effect of high glucose in rat aortic rings. The antioxidant capacity of esquamosan was assessed using DPPH and FRAP assays. Esquamosan exhibited a similar antioxidant capacity compared to ascorbic acid, which was used as a positive control. In conclusion, this lignan showed a vasorelaxant effect, free radical scavenging capacity, and potential reductive power, suggesting its potential beneficial use to treat complex cardiometabolic diseases due to free radical-mediated diseases and its calcium antagonist effect.

The Role of Chloroquine and Hydroxychloroquine in Immune Regulation and Diseases.

Chloroquine (CQ) and hydroxychloroquine (HCQ) are derivatives of the heterocyclic aromatic compound quinoline. These economical compounds have been used as antimalarial agents for many years. Currently, they are used as monotherapy or in conjunction with other therapies for the treatment of autoimmune diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Sjögren's syndrome (SS) and antiphospholipid antibody syndrome (APS). Based on its effects on the modulation of the autophagy process, various clinical studies suggest that CQ and HCQ could be used in combination with other chemotherapeutics for the treatment of various types of cancer. Furthermore, the antiviral effects showed against Zika, Chikungunya, and HIV are due to the annulation of endosomal/lysosomal acidification. Recently, CQ and HCQ were approved for the U.S. Food and Drug Administration (FDA) for the treatment of infected patients with the coronavirus SARSCoV- 2, causing the disease originated in December 2019, namely COVID-2019. Several mechanisms have been proposed to explain the pharmacological effects of these drugs: 1) disruption of lysosomal and endosomal pH, 2) inhibition of protein secretion/expression, 3) inhibition of antigen presentation, 4) decrease of proinflammatory cytokines, 5) inhibition of autophagy, 6) induction of apoptosis and 7) inhibition of ion channels activation. Thus, evidence has shown that these structures are leading molecules that can be modified or combined with other therapeutic agents. In this review, we will discuss the most recent findings in the mechanisms of action of CQ and HCQ in the immune system, and the use of these antimalarial drugs on diseases.

A Compound Isolated from Phyllanthus tenellus Demonstrates Metabolic and Vascular Effects In Vitro.

Common chronic conditions such as metabolic syndrome and diabetes are increasingly associated to metabolic and cardiovascular complications. Although Phyllanthus tenellus leaves have been used in decoctions as a popular remedy to control blood glucose levels and hypertension, its use needs a scientific basis. This study was therefore undertaken to report a phytochemical analysis of P. tenellus leaves and to test if the main active compound has potential to simultaneously tackle several pathophysiological features of metabolic syndrome and diabetes-related metabolic and vascular disorders such as hyperglycaemia, increased platelet activation, and endothelial dysfunction. We performed a partition of the methanolic extract of P. tenellus leaves among different organic solvents followed by chromatographic separation guided by the rat liver microsomal glucose-6-phosphatase assay. Two known tannins were identified by spectroscopic methods as pinocembrin-7-O-[3″-O-galloyl-4″,6″-(S)-hexahydroxydiphenoyl]-α-D-glucose, named P7OG by us, and gemin D. The structural determination of the isolated compounds was based on spectral data. The ability of the main active component, P7OG, to inhibit human platelet aggregation and to modify vascular reactivity of rat aortic rings incubated with high glucose (D-glucose 55 mM) was then evaluated. P7OG was further able to inhibit platelet aggregation induced by adenosine 5'-diphosphate and collagen, showed vasorelaxant effects in arteries precontracted with phenylephrine, and reverted the endothelium-dependent impairment effect of high glucose in rat aortic rings. In conclusion, one tannin isolated from P. tenellus showed promising metabolic, antiaggregant, and vascular effects, which suggests the potential beneficial use of P. tenellus to tackle complex cardiometabolic diseases.

Las estatinas afectan la viabilidad de líneas celulares de leucemia y linfoma humanas in vitro / Statins affect the viability of leukemia cell lines in vitro and human lymphoma

Se ha propuesto que las estatinas inducen apoptosis sobre células tumorales. Para probar dicha hipótesis, se analizó el efecto de las estatinas atorvastatina, fluvastatina, lovastatina, mevastatina, pravastatina y simvastatina en el rango de concentraciones de 1 pM hasta 100 µM, sobre la viabilidad de las líneas celulares humanas Jurkat E6.1, Jurkat D1.1 (Linfoma T) , Daudi (Linfoma B), U937 (leucemia monocítica) y HL-60 (leucemia promielomonocítica) in vitro en cultivos de 48 horas, analizados por la técnica de hidrolización del compuesto bromuro de 3-(4,5-dimetiltiazol-2-il)-2,5-difenilltetrazolio (MTT). Lovastatina y mevastatina son los más potentes inductores de muerte celular independientemente del tipo celular (Ic 50 entre 12 y 50 µM). Para las otras estatinas se observan diferencias en el Ic50 según la línea celular atorvastatina (38,1 y 48,6 µM Jurkats, 55,3 µM Daudi y 100 µM para las otras líneas), pravastatina (25 µM HL-60, 55,6 y 60,7 µM Jurkats y > 100 µM Daudi y U937), simvastatina (25,1 µM Jurkat D1.1, 50,2 µM Jurkat E6.1, 45,2 µM Daudi y 51,3 µM HL-60, y > 100 µM U937) y para fluvastatina en todos los casos > 100 µM. La disminución de la viabilidad celular se revierte completamente cuando las células son incubadas con 10 µM mevalonato. Se concluye que la lovastatina y mevastatina son las más potentes inductoras de muerte seguida por atorvastatina, pravastatina y simvastatina cuyo efecto depende del tipo de línea celular y la fluvastatina no tiene efectos importantes en la viabilidad de las líneas celulares estudiadas

Statins have been proposed to induce apoptosis of tumor cells. In order to test this hypothesis, the effect of atorvastatin, fluvastatin, lovastatin, mevastatin, pravastatin, simvastatin on cell viability was assessed by in vitro culture for 48 hr, at concentrations ranging from 1 pM to 100 µM on human cell lines Jurkat E6.1, Jurkat D1.1 (T cell lymphoma), Daudi (B cell lymphoma), U937 (monocitic leukemia) and HL-60 (pro mielomonocitic leukemia) and analyzed the oxidation of (3-(4.5-Dimethylthiazol-2-yl)-2.5- diphenyltetrazolium bromide (MTT). Lovastatin and mevastatin are the most potent inductors of cell death independently of the cell type (Ic 50 between 12 and 50 µM). Differences in the Ic50 are observed depending on the cell line: atorvastatina (38.1 and 48.6 µM Jurkats, 55.3 µM Daudi y 100 µM for the others lines), pravastatin (25 µM HL-60, 55.6 y 60.7 µM Jurkats and > 100 µM Daudi and U937), simvastatin (25.1 µM Jurkat D1.1, 50.2 µM Jurkat E6.1, 45.2 µM Daudi and 51,3 µM HL-60, and > 100 µM U937) and for fluvastatin > 100 µM in all cases. The decrease in cell viability is reverted completely when the cells were incubated with 10 µM mevalonate. It is concluded that lovastatin and mevastatin are the most potent inductors of cell death followed by atorvastatin, pravastatin and simvastatin whose effect depends upon the cell type and fluvastatin does not have any important effects on cell viability on the cell lines studied

Pharmacological modulation of Th17.

Recently, a third subset of Th17 cells has been described. This T helper subset induces the release of chemokines and growth factors and causes neutrophil accumulation in several mammalian organs. Pharmacological intervention blocking Th17 generation as well as IL-17 signaling might prove useful in a variety of diseases including asthma, chronic obstructive pulmonary disease, Crohn's disease, cystic fibrosis, multiple sclerosis, psoriatic disease and rheumatoid arthritis. Here, we describe the patents that address a potential pharmacological use of promoting or targeting IL-17.

Antinociceptive and anti-inflammatory effects of Croton malambo bark aqueous extract.

Croton malambo (K.) bark aqueous extract, popularly known in Venezuela as "palomatias" or "torco" was tested for acute toxicity and for its anti-inflammatory and antinociceptive effects using tail flick and writhing syndrome tests models, respectively. Croton malambo aqueous extract (6.15 mg/kg i.p.) administered intraperitoneally had a significant antinociceptive and anti-inflammatory effects compared to acetylsalicylic acid (200mg/kg p.o.) and sodium diclofenac (5.64 mg/kg p.o.). Studies to determine correlation between chemical composition and pharmacological activity are underway.